Rocking driver for millstones.



No. 647,049. Pafented Apr. '10, L900.

s. H.,T. TILGHMAN.

ROCKING DRIVER FOR MILLSTONES;

(Application filed May 6, 1899.) (No Model.)

.. m m: 4 ,v I l IN VE N 70/? Z maell i 8 a) I ATTORNEYS.

' rrnn STATES PATENT OFFICE.

SAMUEL H. T. TILGHMAN, .OF IVHITON, MARYLAND.

ROCKING DRIVER FOR MILLSTONES.

SPECIFICATION forming part of Letters Patent No. 647,049, dated April10, 1900.

Application filed May 6, 1899. Serial No. 715,866. (No model.)

To ctZZ whom it may concern:

Be it known that I, SAMUEL H. T. TILGH- MAN, a citizen of the UnitedStates, residing at Whiton, in the county of IVicomico and State ofMaryland, have invented certain new and useful Improvements in RockingDrivers for Millstones; and I do hereby declare the following to be afull, clear, and exact description of the invention,such as will enableothers skilled in the art to which it appertains to make and use thesame.

My invention relates to milling, and more particularly to a new andimproved method or manner of mounting the moving or what is termed therunner stone so that it will be perfectly balanced and sensitivelypoised and held to its work of cooperating with the stationary stone;and, as will be hereinafter fully described and claimed, my inventionconsists in certain novel features of construction and combination ofparts, the preferred embodiment of which willbe clearly set forth in thedrawings made a part of this application.

The object of my invention may therefore be said to consist in theprovision of means for perfectly truing the movable or runner stone of amill and so'connecting it to the spindle or driving-shaft that it willnot be thrown out of its adjusted position and will so receive the forceof the actuating power that such power will be truly applied upon bothsides of the spindle.

While I shall in the following specification and the accompanyingdrawings set forth the preferred construction to be adopted in theproduction of the various details of my invention, it will be understoodthat the substantial equivalent thereof is comprehended by me, and Itherefore do not wish to be strictly confined to the exact showing Ihave made, inasmuch as I wish to include such reasonable modificationsand equivalents as will fairly fall within the scope of my invention.

In the accompanying drawings, Figure 1 is a vertical central section ofthe stationary or bed stone and also of the moving or runner stone andalso showing one way of applying power to the actuating-shaft. Fig. 2 isavertical central section of Fig. 1', taken at right angles thereto.Fig. 3 is a perspective view showing a portion of the stationary stoneand the lower portion of the runner-stone, the upper portion of therunner-stone being entirely cut away in order to expose the detailscomprising my invention. Fig. iis a perspective view showing the top ofthe driving-spindle and my improved driver separated from each other.Fig. 5 shows, re spectively, an end view and a central trans versesection of my improved driver.

Briefly stated, my invention may be said to consist in so connecting thedriving-spindle with the moving or runner stone of a mill that therotation of said spindle will bring its force to bear equally upon bothsides.

It will be understood that in the language of millwrights thedriving-spindle is passed loosely upward through a suitable bearingprovided in the central portion of the bedstone, and the squared andtapered end there of is designed to receive upon its extreme point thebalance-iron or metallic yoke,which is permanently secured to themovable or runner stone and by which said stone is truly balanced andsuspended above the bedstone. The spindle acts upon the runnerstonethrough the mediation of what is termed a driver, which is a cross-piecesecured to the spindle near the end thereof or below said balance-ironor yoke and is of sufficient length to reach into recesses provided inthe stone for its reception, and since said driver is fixedly secured tothe spindle it must rotate therewith and carry with it the movable orrunner stone. The great difficulty arising from the use of thiscross-piece or driver is due to the fact that it is very difficult, ifnot absolutely practically impossible, to so shape the ends of thedriver that they will touch the walls of their respective recessessimulta neously, the difficulty being that even with the most carefulpainstaking adjustment but one of said ends can be brought to bear uponthe wall of the recess in which it loosely fits, the consequence beingthat the runnerstone will not be permitted to remain in a truedposition, but one side thereof will come sharply in contact with thestationary stone, and will consequently drag or bind upon the same,While the opposite side of the stone'is left clear of the bed-stone,with the result that the product of the mill is not uniform,

inasmuch as a portion of the grain will be very finely ground orpulverized, while the remaining portion, acted upon by the separatedsides of the stone, will be coarsely ground, the product being left inan uneven or undesirable condition. It is my purpose therefore toovercome the difficulties which arise as a result of an improper orimperfect coupling between the spindle and the moving or runner stone,and with this end in View I call attention to the details of myinvention and the cooperating accessories thereof, which I shallhereinafter specifically refer to.

In order to designate the several parts of my invention and the partsdesigned to cooperate therewith, numerals will be employed, of which 1illustrates the supportingv base designed to receive and provide afoundation for the bed-stone, said base being constructed in anypreferred way, as by securing together a framework of suitable characterand providing a bed therein of proper size to exactly receive thestationary stone, which may be perfectly trued or leveled into .ahorizontal position.

Within the supporting-base I dispose the stationary or bed stone 2,which will be constructed in any preferred way and which is providedwith the driving-spindle 4, which may be connected with the source ofpower in any preferred manner, as by the gear 5, the lower end of thespindle being preferably conical and properly seated in a supportingbearing 6, all of said parts being substantially of the usual or anyspecial construction desired. The upper end of the spindle 4 is soshaped as to provide the pyramidal or tapered end 7 and the offset orcontinuous shoulder 8 around the same and is further provided with theconical or pointed end 9.

The movable or runner stone 10 is disposed immediately above the fixedor bed stone 2 and is provided with the centrally-disposed eye 11, whichextends entirely through the stone, as is usual. Upon each side of theeye 11 and upon the under side of the runnerstone I form the recesses 12and 13, which are diametrically opposite each other and are designed toreceive the ends of the bail or yoke 14:, the middle portion whereof isdesigned to extend upward into the eye 11 and receives upon the centralpart and under side thereof the conical or pointed end 9, as it is bythis means that the runner-stone is truly balanced or'poised immediatelyabove the bed-stone.

The balance-iron or yoke let is preferably permanently secured inposition, as by means of molten lead poured upon the ends thereof. Itwill be observed by reference to Fig. 1 that the recesses 12 and 13below the ends of the balance-iron are of sufficient extent to looselyor freely receive the ends of my improved driver, which is indicated asa whole by the numeral 15.

The driver now in common use consists of a simple piece of iron providedin its central part with a square hole designed to receive the squaredend of the spindle, to which it is rigidly or permanently attached. Incarrying out my invention I wholly depart from this method of connectingthe driver with the spindle, inasmuch as I taper the squared portion orend of the spindle and provide a square aperture 16 in the middle of thedriver, which is of larger size at its upper end, the result being thatthe lower end of the aperture will snugly or tightly fit around the baseportion of the pyramidal section 7, while the upper end of the hole willnot touch said portion, the result being that the driver is left free torock and adjust itself to the section 7.

In order to provide an additional adjustability for the driver, I soconstruct the ends 17 thereof that the sides will be inwardly anddownwardly tapered, thus leaving the upper edges of said ends of widerextent, thereby producing the bearing edges 18, which alone contact withthe wall of the recess in which they are disposed, and in order tofacilitate the free movement of the driver, that it may accommodateitself to its work, I so construct the lower side of the driver that itwill have a curved surface or present the swell or pointed middleportion 19, which is designed to rest upon the offset or shoulder 8, andthereby permit the driver to freely rock when it is in the act ofaccommodating itself, so as to bring each end thereof to bear equallyagainst the runner-stone at points upon each side of the spindle. Itwill be understood that the spindle may be so adjusted that the shoulder8 thereof will rest slightly above the surface of the bed-stone, therebyinsuring that the ends of the driver will clear the bed-stone and thebushing.

While I have shown the entire under surface of'the ends of mydriver asbeing rounded or provided with the swell 19, it will be understood thatsince only that portion of the driver immediately on each side of theaperture 16 comes in contact with the shoulder 8 the remaining portionof the ends not in contact with said shoulder may be left straight orparallel with the upper portion in order that the extreme ends of thedriver may not ride over the grain, but may direct said grain betweenthe stones.

By reference to Figs. 1 and 2 it will be observed that the upper portionof the walls of the aperture 16 is wholly out of contact with thepyramidal section 7, the lower edges of said aperture only being incontact with said section, which enables the driver to freely rock, andthereby adjust itself so that each end thereof will heal-equally againstthe wall of its respective recess, and thereby equally distribute theforce brought to bear upon the stone.

In Fig. 3 I have illustrated simply the lower edge of the runner-stone10, as I have wholly cut away the upper portion of the stone on a lineimmediately above the surface of the driver, therefore leaving saiddriver and the recesses wholly exposed. In this View the driver is shownto be in its operative position, ready to turn the runner-stone in thedirection indicated by the arrow, and special at tention is thereforecalled to the position of the driver, inasmuch as it will be seen thatsaid driver is not disposed in a truly-horizontal position, as one edgethereof is higher than the other, thus showing that the driver hasturned or rocked slightly in order to accommodate itself upon thetapered or pyramidal section and also bring its upper edges to bearagainst the walls of the recesses in which the ends of the driver areloosely disposed. It will be further observed that an opening or space20 is left between the upper edge of the aperture 16 and one side ofthepyramidal section 7, while upon the opposite side, as indicated bythe numeral 21, said parts are shown to be in close contact with eachother. It will be further observed, as indicated by the numeral 22, thatthe upper edge of one end of the driver is in close contact with thewall of its recess, while the opposite edge of the opposite end, asindicated by the numeral 23, is in contact with the wall of its recess.

It is obvious that if the tapered or pyramidal section 7 was adapted tofit tightly in the recess 16, as would be the case if the walls of bothof said parts were vertical, the result would be that the driver couldnot tip-to one side or rock, and the ends thereof could not, therefore,accommodate themselves so that each would hear equally upon the stone.

The essential feature, therefore, of my invention consists in shapingthe driver, the

- pyramidal section 7, and the aperture 16 and combining them in themanner specified.

It will be readily appreciated that it is a very important matter tokeep the runnerstone truly adjusted, as when so disposed the result willbe that the stones are not so readily dulled or injured by contactingwith each other, while the product is absolutely uniform andconsequently more desirableand valuable. It is further obvious that as aresult of perfect adjustment and the employment of means to permanentlypreserve such adjustment less power will be required to operate themill, while the resultant heat due to the contact of the stones will begreatly reduced, the consequence being that the product or ground grainwill be delivered with a much lower temperature or in acomparatively-cool state.

Inasmuch as the driver is left free to rock in the manner specified, itis obvious that it will readily adjust itself so that both ends will betruly in contact with the runner-stone without regard to the directionwhich the spindle may be rotated, thereby enabling the runner-stone tobe freely reversed at will with the full assurance that it will remainundisturbed or removed from a true horizontal po sition.

WVhile I have illustrated the balance-iron or yoke 14 'as being disposedparallel with the driver and in the same recess occupied there by, itwill be understood that equally-desirable results may be obtained bydisposing the driver in recesses made at right angles to the recessesoccupied by the ends of the yoke, and I desire, therefore, to reservethe right to make either disposition, as I may deem productive of thebest results.

It is further obvious that while I have disposed the aperture 16 asbeing squarely at right angles to the longitudinal plane of the driversaid hole may be obliquely disposed, if desired, in which case thecorners of the pyramidal section would be adjacent to the sides ormiddle portion of the driver, thus enabling the ordinary form of drivernow in common use and having the obliquely-disposed hole to be readilychanged so as to comprise the other features of my invention, as byenlarging the upper end of the aperture upon every side and rounding thelower side of the driver, as specified.

Having thus fully described the construction and use of my invention,what I claim as new, and desire to secure by Letters Patent, is

1. In mills, the combination with a running-bur formed with shouldersand a central aperture, and a spindle formed with an angular taperingupper extremity, of a drivin g-block having a central aperture ofgreater size than the upper extremity of the spindle and adapted to fitover the spindle, said block having also extended ends or arms providedwith downwardly and inwardly tapered sides, and a convex bottom restingupon a shoulder upon the spindle and permitting the rocking of therunner, as set forth.

2. The herein-described block havinga centrally-disposed aperture ofgreater size at its upper end, the ends of the block being provided withinwardly and downwardly tapered sides, whereby the upper surface of theblock will be of greatest width, thereby bringing its edges to bearagainst the walls of the recess formed in the millstone, said centralaperture permitting'said block to rock or adjust itself in order toinsure that both ends thereof will bear equally upon the millstone inthe manner specified and for the purpose set forth.

In testimony whereof I affix my signature in presence of two witnesses.

his SAMUEL H. T. X TILGHMAN.

m ark Witnesses:

HERBERT E. TREADWELL, E. E. OVERHOLT.

